Analysis and Design Considerations for On-Chip Power Supply Inductance




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Sanjay Pant

Power supply integrity has become a critical concern in modern chip design.  To date, analysis of so-called LdI/dt drop in supply networks has mostly focused inductance of the package, which is the predominant factor in inductive voltage drop. However, with increased clock frequencies and power supply demands, on-chip inductance has become a significant factor in the total LdI/dt drop. In this work, we analyze the impact of on-chip inductance on power supply integrity and propose methods that significantly reduce the voltage drop caused by on-chip inductance. We develop a detailed model of a flip-chip supply network based on an industrial design. The model includes an accurate package model, a PEEC-based model of the on-chip supply interconnects and both intrinsic and explicit on-chip decoupling capacitance.  We show that on-chip inductance can account for up to 30% of the total voltage drop in the Giga Hertz processor domain and propose two new on-chip power supply topologies that reduce the on-chip LdI/dt drop by 70%.


Analysis and Reduction of On-Chip Inductance Effects in Power Supply Grids

Woo Hyung Lee, Sanjay Pant, David Blaauw, “Analysis and Reduction of On-Chip Inductance Effects in Power Supply Grids”, ACM/IEEE International Symposium on Quality Electronic Design (ISQED), March 2004, og. 131-136. ©IEEE